Introductory information will here be provided. Note, however, that the apparatus, techniques, or schemes described herein as existing or possible are presented only as background for describing the present invention, and no admission is intended thereby that these were heretofore commercialized or known to others beside the inventors.
Selected abbreviations are herewith defined, at least some of which are referred to within the following description of the state-of-the-art and the present invention.    ASIC Application Specific Integrated Circuit    CAC Call Admission Control    CRL Certificate Revocation List    DHCP Dynamic Host Configuration Protocol    DSL Digital Subscriber Line    DVR Digital Video Recorder    HA Home Agent    FA Foreign Agent    IEEE Institute of Electrical and Electronics Engineers    IP Internet Protocol    ISP Internet Service Provider    NAT Network Address Translation    OS Operating System    OSS Operations Support Systems    PC Personal Computer    PKI Public Key Infrastructure    PS Proxy Server    RG Residential Gateway    SG Signaling Gateway    QoS Quality of Service    TCP Transmission Control Protocol    UID Unique Identifier
Consumer electronics have progressed a great deal in the recent past. Not only are they more capable than they were a short time ago, they are also far more prevalent. Many homes, for example, have more than one personal computer and video storage device, along with many similar devices. These devices are often connected together to form a network, and through the network are capable of communicating with other devices outside of the home. The use of email and telephone services that are available through such networks is very common, and the downloading of, for example, software applications and multimedia transmissions is becoming more frequent.
A home network benefits users in a number of ways. Even if there is no connection to others outside of the home, the home network allows a user to, for example, print from a printer that is not connected directly to the computer in use. Files such as documents, pictures, and videos may be retrieved or sent to another device within the home. Modern data storage units are capable of saving a large amount of audio or video data, and the network permits this content to be retrieved and played on any device connected to the network. Multiple users may participate in a game over the network.
Connections outside of the home are often facilitated by some type of device that serves as an interface to whatever network service is providing access. Such a device may take the form, for example, of a wireless router connecting multiple computers to the Internet, or a set-top box that receives video and television programming for display on a television or other video display device. Many if not most home networks are connected to an access network, which provides a link between a subscriber's home and a core network capable of handling large amounts of communication traffic and providing gateways for communicating through other networks as well.
When the home network is connected to an access network, communications such as email and Internet access are permitted; video and audio content may be downloaded. In addition, recent advances in technology have enlarged the amount of data that may be uploaded, or sent from the home network to others through the access network. In some cases, for example a movie or other video may be sent to another at nearly the speed at which it was downloaded, at least from the user's perception.
This may be of great advantage to the user of a mobile device. As used herein, a mobile device is one capable of accessing a mobile network using radio communications. Mobile devices are very popular because of their mobility; a user may conveniently carry the device with them and use it anywhere a mobile network may be contacted. Mobile network providers have signed up thousands of subscribers and built up networks that cover large geographic areas. In many locations, if a subscriber cannot access their own mobile network, they may use another network as a visitor. Mobile networks are often based on a cell system, where mobile devices communicate with a nearby base station and handover protocols allow them to travel from one cell (base station) to another without significant interruption of an on-going communication session.
A mobile subscriber at home may be able to access content and devices that are part of the home network, for example using a short range radio protocol such as Bluetooth. When the user is not at home, however, such access is not available, but the content may be accessible in a number of other ways. For example, content accessible via the home network may not actually be stored there, but is rather stored in a remote memory device maintained by a vendor. In other cases the content may be stored within the home network, but is copied or mirrored at a vendor's server for the purpose of providing mobile access. In either case, the user may access the content being stored by the vendor using a mobile device communicating though a mobile network.
There are disadvantages with this strategy, however. For one, storage on a vendor site may raise security concerns. In addition, the vendor may charge for the service and there is a risk that they may at some point become unavailable if their business fails. Finally, the sheer volume of content that users currently want to, and are projected to demand, may make this option less than viable in the future.
Access may also be possible directly to the home network though a mobile network using protocols such as MobileIP. In such an arrangement it is contemplated that the mobile device embodies a foreign agent (FA) that establishes a communication session with a home agent (HA) embodied on one of the devices that makes up the home network. Although this addresses some of the disadvantages associated with third party vendors, several disadvantages remain.
First, to communicate with the FA, the HA obtains an IP address. In general practice, however, this IP address will be dynamically assigned, meaning that he address is not assigned permanently but will eventually be re-assigned to another user. Of course, the HA can request another IP address, but when assigned it will almost certainly be different than the previous one. While the policy of dynamically assigning IP addresses conserves IP addresses and reduces the number ultimately required, it can disrupt routing between the FA and the HA and make it more difficult for the mobile device to register with its respective HA.
In addition, home networks frequently employ a residential gateway, with the HA being assigned a private IP address and being behind a NAT boundary. This also may help to conserve IP addresses, but may make it difficult for the FA to contact the HA and set up a secure tunnel for communications.
In the face of such difficulties, there is a need for a manner of facilitating secure access to a home network from a remote mobile station. Accordingly, there has been and still is a need to address the aforementioned shortcomings and other shortcomings associated with communications between a FA embodied in a mobile device and an HA in a home network. These needs and other needs are satisfied by the present invention.